The present invention relates to the field of functional analysis of Jatropha genes on a genomic scale. More specifically, the present invention relates to a method for high-throughput functional analysis of Jatropha curcas genes on a genomic scale using virus-induced gene silencing.
The publications and other materials used herein to illuminate the background of the invention or provide additional details respecting the practice, are incorporated by reference, and for convenience are respectively grouped in the Bibliography.
The world is facing dwindling supply is fossil fuel and worsening Green House Effect. There is an urgent demand to increase production and consumption of renewable energy. Biofuels have been recognized as a national priority for many countries in their search for alternative sources to meet their energy security needs and at the same time help reduce CO/emissions that cause the Green House Effect. The demand for biofuel has put increasing pressure on food production. For example, to satisfy the biofuel need for Germany in 2017 as mandated by the German government the entire farm land of this country would have to be used for growing bioenergy crops with no land left for food production. To ease this competition for land and to satisfy our need for renewable fuels, there is a strong need to utilize marginal land for bio-energy production.
Jatropha curcas is a small woody plant belonging to the Euphorbiaceae family. Several unique characters of Jatropha curcas make it an ideal plant for biodiesel production. These include its rapid growth, easy propagation, low cost of seeds, high oil content, short gestation period, wide adaptability, drought tolerance and the ability to thrive on degraded soils. Moreover, its plant size renders convenient collection of seed (Jones, 1991; Sujatha et al., 2008).
However, Jatropha suffers from several shortcomings that may limit its wide adoption. The productivity of the plant is constrained by the unfavourable male to female flower ratio and its oil content has not been optimized by breeding. This plant is also sensitive to biotic stresses such as viral (Narayanna et al., 2007), fungal and bacterium pathogens and abiotic stresses, especially cold and drought (http colon www dot jatropha dot org). The presence of several toxic components (e.g. the protein toxin, curcin, and the cancer-causing agent phorbol esters) in seeds and leaves of the plant possess health hazards for farmers and bioprocess workers in the Jatropha industry.
An important strategy to improve agronomic and quality traits of Jatropha curcas is by genetic modification. Transgenic Jatropha plants can be generated expressing homologous or heterologous gene sequences. In many instances, over-expression or silencing by RNAi of one or more homologous genes of defined function is desired. Gene sequences of Jatropha can be obtained from cDNA and genomic libraries and functions of genes can be tentatively assigned by sequence homology with other plant genes of known function. However, such assignment at best is only provisional and tentative. Quite often functional assignment is confounded by the presence of a gene family whose members are highly related in sequences. Gene function can be more accurately determined by over-expression or RNAi-mediated silencing of candidate genes in transgenic plants; however, such procedure is laborious and time consuming and not suitable for high throughput analysis on a genomic scale.
Thus, it is desired to develop a method for the high-throughput functional analysis of Jatropha curcas genes on a genomic scale.